Method for availability monitoring via a shared database

Abstract

A technology for indicating and determining the availability of a multitude of application servers. The method comprises for each of application server a first step of inserting into an availability database a notification period defining an upper time limit for a repetition period of an availability signal, which is repeated as long as the application server is available. In a second step for each availability signal its corresponding time stamp is inserted as availability time into the availability database. The difference of the current time and a recent availability time compared to said notification period is representing a measure of availability for the application servers.

1. A computerized method for indicating availability of one or a multitude of application-servers, comprising:
 said method comprising a first step of inserting into a central availability-database a first-data-element comprising a notification-period, said notification-period defining an upper time limit for a repetition period of an availability-signal being repeated as long as said application-server is available;  
 said method comprising a second step of inserting into said central availability-database a second-data-element comprising for each availability-signal its corresponding time stamp as availability-time;  
 whereby, the difference of the current-time and a recent availability-time compared to said notification-period is representing a measure of availability of said application-server; and  
 said method comprising a third step of updating said notification-period depending on the amount of workload of said application-server 
 either by increasing said notification-period, if said amount of the workload increases,  
 or by decreasing said notification-period, if said amount of the workload decreases.  
 
 
     
     
       2. A computerized method for indicating availability according to  claim 1 , comprising:
 wherein within said first and said second step also an application-server-identification is inserted into said central availability-database and associated with said first- and said second-data-element.  
 
     
     
       3. A computerized method for indicating availability according to  claim 2 , comoprising:
 wherein said measure of availability indicates unavailability of said application-server, if said difference exceeds said notification-period.  
 
     
     
       4. A computerized method for indicating availability according to  claim 1 , comprising:
 wherein said central availability-database is shared by a multitude of application-servers each comprising a hot-pool of said one or multitude of application-servers;  
 wherein for said hot-pool a watchdog is monitoring said hot-pool's availability status;  
 wherein said method is being executed by said watchdog;  
 wherein said availability-signal is being repeated as long as at least one of said application-servers of said hot-pool is available; and  
 wherein within said first and said second step also a hot-pool-identification is inserted into said central availability-database and is associated with said first- and said second-data-element.  
 
     
     
       5. A computerized method for indicating availability according to  claim 1 , comprising:
 whereby as a second difference the difference of said recent availability-time and a previous availability-time is included in said measure of availability.  
 
     
     
       6. A computerized method for indicating availability according to  claim 4 , comprising:
 whereby as a second difference the difference of said recent availability-time and a previous availability-time is included in said measure of availability.  
 
     
     
       7. A computerized method for determining availability of one or multitude of application-servers for accepting application-service-request, comprising:
 said method comprising a first step of querying a central availability-database 
 for a first-data-element comprising a notification-period, said notification-period defining an upper time limit for a repetition-period of an availability-signal being repeated as long as said application-server is available;  
 for a second-data-element comprising for a recent availability-signal its time-stamp as recent availability-time;  
 
 said method comprising a second step of determining a measure of availability of said application-server by comparing the difference of the current-time and said recent availability-time to said notification-period;  
 said method comprising a third step of issuing an application-service-request to said application-server only, if said measure of availability indicates availability of said application-server; and  
 said method comprising a fourth step of updating said notification-period depending on the amount of workload of said application-server 
 either by increasing said notification-period, if said amount of the workload increases,  
 or by decreasing said notification-period, if said amount of the workload decreases.  
 
 
     
     
       8. A computerized method for determining availability according to  claim 7 , comprising:
 wherein said method is querying in said first step also for a third-data-element comprising a previous availability-time for a previous availability-signal; and  
 wherein in said second step also as a second difference the difference of said recent availability-time and said previous availability-time is included in said measure of availability.  
 
     
     
       9. A computerized method for determining availability according to  claim 7 , comprising:
 wherein said measure of availability indicates unavailability of said application-server, if said difference exceeds said notification-period by a factor of N.  
 
     
     
       10. A computerized method for determining availability according to  claim 8 , comprising:
 wherein said method is being executed for a multitude of application-servers;  
 wherein in said third step 
 a subset of application-servers, comprising application-servers for which said measure of availability indicates availability, is determined, and  
 for each application-server within said subset its corresponding measure of availability is interpreted as a workload indications; and  
 said application-service-request is being issued to an application-server with the lowest workload.  
 
 
     
     
       11. A system indicating availability of one or a multitude of application-servers, said system comprising:
 a first device for inserting into a central availability-database a first-data-element comprising a notification-period, said notification-period defining an upper time limit for a repetition period of an availability-signal being repeated as long as said application-server is available;  
 said device further inserts into said central availability-database a second-data-element comprising for each availability-signal its corresponding time stamp as availability-time;  
 whereby, the difference of the current-time and a recent availability-time compared to said notification-period is representing a measure of availability of said application-server; and  
 said device updates the notification-period depending on the amount of workload of said application-server 
 either by increasing said notification-period, if said amount of the workload increases,  
 or by decreasing said notification-period, if said amount of the workload decreases.  
 
 
     
     
       12. A data processing program for execution in a data processing system comprising software code portions, said software code portions comprising:
 a first software code portion for inserting into a central availability-database a first-data-element comprising a notification-period, said notification-period defining an upper time limit for a repetition period of an availability-signal being repeated as long as an application-server is available;  
 a second software code portion for inserting into said central availability-database a second-data-element comprising for each availability-signal its corresponding time stamp as availability-time;  
 whereby, the difference of the current-time and a recent availability-time compared to said notification-period is representing a measure of availability of said application-server; and  
 a third software portion for updating said notification-period depending on the amount of workload of said application-server 
 either by increasing said notification-period, if said amount of the workload increases,  
 or by decreasing said notification-period, if said amount of the workload decreases.  
 
 
     
     
       13. A computer program product stored on a computer usable medium, comprising a computer readable program embodied in said medium, comprising:
 readable code for inserting into a central availability-database a first-data-element comprising a notification-period, said notification-period defining an upper time limit for a repetition period of an availability-signal being repeated as long as an application-server is available, and;  
 readable code for inserting into said availability-database a second-data-element comprising for each availability-signal its corresponding time stamp as availability-time,  
 whereby, the difference of the current-time and a recent availability-time compared to said notification-period is representing a measure of availability of said application-server; and  
 readable code for undating said notification-period depending on the amount of workload of said application-server 
 either by increasing said notification-period, if said amount of the workload increases,  
 or by decreasing said notification-period, if said amount of the workload decreases.  
 
 
     
     
       14. A system for determining availability of one or multitude of application-servers for accepting application-service-request, said system comprising:
 a first device for querying a central availability-database 
 for a first-data-element comprising a notification-period, said notification-period defining an upper time limit for a repetition-period of an availability-signal being repeated as long as said application-server is available, and  
 for a second-data-element comprising for a recent availability-signal its time-stamp as recent availability-time;  
 
 said device determines a measure of availability of said application-server by comparing the difference of the current-time and said recent availability-time to said notification-period;  
 wherein said device issues an application-service-request to said application-server only, if said measure of availability indicates availability of said application-server; and  
 said device updates the notification-period depending on the amount of workload of said application-server 
 either by increasing said notification-period, if said amount of the workload increases,  
 or by decreasing said notification-period, if said amount of the workload decreases.  
 
 
     
     
       15. A data processing program for execution in a data processing system comprising software code portions, said software code portions comprising:
 a first software code portion for querying a central availability-database 
 for a first-data-element comprising a notification-period, said notification-period defining an upper time limit for a repetition-period of an availability-signal being repeated as long as said application-server is available, and  
 for a second-data-element comprising for a recent availability-signal its time-stamp as recent availability-time;  
 
 a second software code portion to determine a measure of availability of said application-servers by comparing the difference of the current-time and said recent availability-time to said notification-period;  
 a third software code portion to issue an application-service-request to said application-server only, if said measure of availability indicates availability of said application-server; and  
 a fourth software code portion for updating said notification-period depending on the amount of workload of said application-server 
 either by increasing said notification-period., if said amount of the workload increases,  
 or by decreasing said notification-period, if said amount of the workload decreases.  
 
 
     
     
       16. A computer program product stored on a computer usable medium, comprising a computer readable program embodied in said medium comprising:
 readable code for querying a central availability-database 
 for a first-data-element comprising a notification-period, said notification-period defining an upper time limit for a repetition-period of an availability-signal being repeated as long as said application-server is available, and  
 for a second-data-element comprising for a recent availability-signal its time-stamp as recent availability-time;  
 
 readable code for determining a measure of availability of said application-server by comparing the difference of the current-time and said recent availability-time to said notification-period;  
 readable code for issuing an application-service-request to said application-server only, if said measure of availability indicates availability of said application-server; and  
 readable code for updating said notification-period depending on the amount of workload of said application-server 
 either by increasing said notification-period, if said amount of the workload increases,  
 or by decreasing said notification-period, if said amount of the workload decreases.  
 
 
     
     
       17. A computerized method for determining availability according to  claim 7 , comprising
 wherein said measure of availability of the second step indicates unavailability of said application-server, if said difference exceeds said notification-period.